Electron beam emitter for sterlizing containers

ABSTRACT

An electron beam emitter including a vacuum chamber having a width. An electron generator can be positioned within the vacuum chamber for generating electrons. An elongate nozzle can extend from the vacuum chamber along a longitudinal axis and have an exit window at a distal end of the nozzle. The nozzle can have a width that is less than the width of the vacuum chamber. The electron generator can be shaped and dimensioned, and positioned with the vacuum chamber to form and direct a narrow electron beam that enters and travels through the nozzle, and exits out the exit window.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.60/773,047, filed on Feb. 14, 2006. The entire teachings of the aboveapplication are incorporated by reference.

BACKGROUND

Electron beam emitters have been used for irradiating and sterilizingcontainers with electron beams. Typically, an electron beam emitter ispositioned above the container and directs an electron beam downwardlyinto the container. However, when the container is a bottle with anarrow neck, adequate sterilization of the bottle becomes difficult. Anarrow neck can block a large portion of the electron beam from enteringthe bottle.

SUMMARY

The present invention can provide an electron beam emitter including avacuum chamber having a width. An electron generator can be positionedwithin the vacuum chamber for generating electrons. An elongate nozzlecan extend from the vacuum chamber along a longitudinal axis and have anexit window at a distal end of the nozzle. The nozzle can have a widththat is less than the width of the vacuum chamber. The electrongenerator can be shaped and dimensioned, and positioned within thevacuum chamber to form and direct a narrow electron beam that enters andtravels through the nozzle, and exits out the exit window.

In particular embodiments, the nozzle can have a generally circularperiphery, and a diameter. The vacuum chamber can have a generallycircular periphery, and have a diameter that is larger than the diameterof the nozzle. The electron generator can have a housing with a diameterthat is about the same as the diameter of the nozzle. The electrongenerator can be shaped and dimensioned, and positioned to form theelectron beam with a converging portion that converges within thenozzle, followed by diverging portion that diverges within the nozzlebefore reaching the exit window. The electron beam can further divergeafter exiting the exit window. The electron generator can include anelectron generating filament that has a portion oriented generallylongitudinally in line with the longitudinal axis of the nozzle. Thenozzle can have a length, and a length to diameter ratio of at leastabout 3:1. The emitter can have a vacuum chamber diameter to nozzlediameter ratio of at least about 2:1.

The present invention can also provide a method of generating anelectron beam, including generating electrons with an electron generatorpositioned within a vacuum chamber, the vacuum chamber having a width.An elongate nozzle can extend from the vacuum chamber along alongitudinal axis. The nozzle can have an exit window at a distal end ofthe nozzle. The nozzle can have a width that is less than the width ofthe vacuum chamber. The electron generator can be shaped anddimensioned, and positioned within the vacuum chamber to form and directa narrow electron beam that enters and travels through the nozzle andexits out the exit window.

In particular embodiments, the nozzle can have a generally circularperiphery, and a diameter. The vacuum chamber can have a generallycircular periphery, and a diameter that is larger than the diameter ofthe nozzle. The electron generator can have a housing with a diameterthat is about the same as the diameter of the nozzle. The electrongenerator can be shaped and dimensioned, and positioned to form theelectron beam with a converging portion that converges within thenozzle, followed by a diverging portion that diverges within the nozzlebefore reaching the exit window. The electron beam can further divergeafter exiting the exit window. The electron generator can include anelectron generating filament. A portion of the filament can be orientedgenerally longitudinally in line with the longitudinal axis of thenozzle. The nozzle can have a length, and a length to diameter ratio ofat least about 3:1. The vacuum chamber and the nozzle can have a vacuumchamber diameter to nozzle diameter ratio of at least about 2:1.

The present invention can also provide a method of irradiating aninterior of a bottle, in which the bottle has a neck. Electrons can begenerated with an electron generator positioned within a vacuum chamber,the vacuum chamber having a width. An elongate nozzle can extend fromthe vacuum chamber along a longitudinal axis. The nozzle can have anexit window at a distal end of the nozzle. The nozzle can have a widththat is less than the width of the vacuum chamber. The electrongenerator can be shaped and dimensioned, and positioned within thevacuum chamber to form and direct a narrow electron beam that enters andtravels through the nozzle, and exits out the exit window. The nozzlecan be inserted through the neck of the bottle and irradiate theinterior with the electron beam.

In particular embodiments, the elongate nozzle can have a generallycircular periphery, and a diameter. The vacuum chamber can have agenerally circular periphery, and a diameter that is larger than thediameter of the nozzle. The electron generator can have a housing with adiameter that is about the same as the diameter of the nozzle. Theelectron generator can be shaped and dimensioned, and positioned to formthe electron beam with a converging portion that converges within thenozzle, followed by a diverging portion that diverges within the nozzlebefore reaching the exit window. The electron beam can further divergeafter exiting the exit window. The electron generator can include aelectron generating filament having a portion oriented generallylongitudinally inline with the longitudinal axis of the nozzle. Thenozzle can have a length, and a length to diameter ratio of at leastabout 3:1. The vacuum chamber and the nozzle can have a vacuum chamberdiameter to nozzle diameter ratio of at least about 2:1. The bottle andthe nozzle can be moved relative to each other during irradiation. Thedistribution of the electron beam within the interior of the bottle canbe assisted with at least one electron directing member adjacent to thebottle. The interior of the bottle can have an ambient gaseousenvironment. The gaseous environment can be modified within the bottle.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing will be apparent from the following more particulardescription of example embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingembodiments of the present invention.

FIG. 1 is a side schematic view of an embodiment of a sterilizationsystem;

FIG. 2 is a perspective exploded view of an electron beam emitter havinga nozzle;

FIG. 3 is a side schematic view of a nozzle of an electron beam emitterinserted into a bottle;

FIG. 4 is aside schematic view of a portion of an electron beam emitterwith a nozzle;

FIG. 5 is a perspective view of an electron beam gun or generator;

FIG. 6 is a schematic sectional view of the electron beam generator ofFIG. 5; and

FIGS. 7-11 are schematic drawings of filaments having circular portions.

DETAILED DESCRIPTION

A description of example embodiments follows. Referring to FIG. 1,sterilization system 15 can include an electron beam emitter 10 having avacuum chamber 11. A pipe, conduit, tube or nozzle 12 (FIG. 2) canextend from, and be connected or secured and sealed to the axial end 10a of the vacuum chamber 11. An electron beam 44 can be emitted throughthe nozzle 12. The nozzle 12 can be narrow and elongate, allowing thenozzle 12 to be inserted into the opening 16 a of a narrow neck 16 of acontainer such as a bottle 20, for irradiating the interior 18 of thebottle 20 with the electron beam 44 to irradiate, treat or sterilizesurfaces in the interior 18. The vacuum chamber 11 can remain outsidethe bottle 20 while the nozzle 12 is inserted in the neck 16. Electricalpower to electron beam emitter 10 can be provided by a power source 13via lines 17 a and 17 b.

The interior 18 of the bottle 20 can be irradiated as the nozzle 12 isinserted and/or withdrawn from the bottle 20, or after insertion. Thedistance in which the nozzle 12 is inserted into the bottle 20 candepend upon the size of the bottle 20, including the height, width ordiameter, as well as the intensity of the electron beam 44. Treatment orsterilization of the interior of the bottle 20 can be achieved by one ormore of disabling, killing, destroying, vaporizing, oxidizing, altering,etc., microorganisms and biological substances within the interior 18and on the interior surfaces 20 a of the bottle 20. In addition,non-biological substances can be treated to neutralize, reduce or removeharmful effects.

The bottle 20 can be positioned on a support 50 which can move thebottle 20 up and down, or relative to the nozzle 12. If desired, thesupport 50 can also be rotated for rotating the bottle 20 to evenlyirradiate the interior 18 of the bottle 20. Alternatively, the electronbeam emitter 10 can be moved up and down, or relative to the bottle 20,and/or rotated. One or more electron shaping, spreading or directingplates or members 52 can be provided adjacent to the bottle 20 fordistributing, shaping, spreading, directing or assisting electrons e⁻ inthe electron beam 44 (FIG. 3) to reach the interior surfaces 20 a of thebottle 20 in a desired manner, or pattern or configuration, fortreatment or sterilization. The electron directing members 52 can assistthe distributing, shaping, spreading or directing of the electrons e⁻with magnetism, or electric potential or charge. One or more electrondirecting members 52 can be located at one or more locations laterallyadjacent to the bottle 20, or alternatively, surround the exterior ofthe bottle 20 laterally circumferentially. In addition, the support 50can also be used as a shaping, spreading or directing plate or member,for distributing, shaping, spreading directing, or assisting electronse⁻ to the bottom interior surface 20 b of the bottle 20 in a desiredmanner, pattern or configuration. The support 50 can be provided withmagnets, or electric potential or charge. The electron directing members52 and the support 50 can receive power from power source 13.

If desired, a light gas 56 (FIG. 3) such as helium can be introducedinto the bottle 20 by a nozzle or tube 54 to modify the ambient orexisting gaseous environment and increase the range of the electron beam44. In addition, the gas 56 can be used to form a plasma in conjunctionwith the electron beam 44, which can assist the treatment orsterilization process. Alternatively, nozzle or tube 54 can be a vacuumnozzle or tube for removing air from the bottle 20 to modify the gaseousenvironment, creating a vacuum or a partial vacuum. This can alsoincrease the range of the electron beam 44 and assist in the treatmentor sterilization process.

Referring to FIGS. 3-6, vacuum chamber 11 of the electron beam emitter10 can be generally cylindrical and elongate in shape with a width ordiameter D₁ (FIG. 4). The nozzle 12 can also be generally cylindrical ortubular in shape with a length L₁, an outer width or diameter D₂, and aninner width or diameter D₃. The nozzle 12 can be inserted into smallopenings that would be too small to allow the insertion of an electronbeam emitter 10 which did not have a narrow nozzle 12, and instead hadan exit window 42 at the axial end 10 a of the vacuum chamber 11. Havingvacuum chamber 11 with a diameter D₁ that is larger than the diameter D₂of the nozzle 12 can allow the electron beam emitter 10 to operate athigher power than if the electron beam emitter 10 were constructed tohave a single small diameter of the same size as the nozzle 12. Thevacuum chamber 11 and nozzle 12 can be joined together in a manner tohave a permanent hermetically sealed vacuum therein.

An electron gun or generator 24 for generating the electrons e⁻ can bepositioned within the interior 22 of the vacuum chamber 11, a distanceL₂ from the axial proximal end of the nozzle 12, and a distance L₃ fromexit window 42 at the axial distal end 14 of nozzle 12. The electrongenerator 24 can include a housing 26 which can be generally cylindricalin shape with a circular periphery, and can have a width or diameter D₄.The housing 26 can include two housing portions 26 a and 26 b which arejoined together (FIGS. 5 and 6). The sides of the housing 26 can bespaced from the interior surfaces 11 a of the vacuum chamber 11 by adistance of W which can provide a high voltage gap. An electrongenerating filament 32 can be positioned within the interior 34 of thehousing 26. Power to the electron generating filament 32 can be providedfrom power source 13 through leads 32 a and 32 b, which can extend fromhousing 26 through an insulator 28. The electron generating filament 32can have a portion that is longitudinally positioned in an orientationthat is generally in line with the longitudinal axis “X” of the nozzle12 and vacuum chamber 11 (FIG. 4). The electron generating filament 32can have a slight V-shape (FIG. 6), with leads 32 a and 32 b extendingfrom a distal end or point 33 at an angle from each other and towardsthe insulator 28. The electron generating filament 32 can generate freeelectrons e⁻ when heated by electrical power passing through thefilament 32. The general inline orientation of the electron generatingfilament 32 in electron generator 24 can provide electrons e⁻ in aconfiguration, arrangement, or location, that is suitable for beingfocused, or shaped and conveyed or directed through the nozzle 12. TheV-shape of the electron generating filament 32 can also provideelectrons e⁻ in a suitable configuration. The electron generatingfilament 32 can extend through an opening 36 in an electrostatic,focusing or shaping lens or member 30. The electrostatic lens 30 canprovide initial focusing or shaping of the electrons e⁻ and can haveopenings 40 for aiding in providing the desired focus. The axial end ofthe housing 26 can have an electron permeable or emitting region oropening 38 with a diameter D₅, through which the electrons e⁻ from thefilament 32 and electrostatic lens 30 pass, and which can form anotherelectrostatic focusing or shaping lens or member for further focusing orshaping the electrons e⁻ emitted from electron generator 24. Highvoltage potential can be provided between housing 26 of the electrongenerator 24 and the exit window 42 by power source 13. The exit window42 can have a ground 48. The voltage potential between the electrongenerator 24 and the exit window 42 can accelerate the electrons e⁻emitted by the electron generating filament 32, from the electrongenerator 24 towards and through the exit window 42. Although theelectron generating filament 32 is typically longitudinally positioned,in some embodiments, the electron generating filament 32 can belaterally positioned. In addition, in some embodiments, multiplefilaments 32 can be employed. Furthermore, the electron generatingfilament 32 can be a laterally or longitudinally positioned generallycircular filament. Examples of some embodiments are depicted in FIGS.7-11. FIGS. 8-11 depict examples where the filament 32 is bent to have agenerally circular outer filament portion that substantially surrounds agenerally circular inner filament portion.

The electron generator 24 can be positioned within the interior 22 ofthe vacuum chamber 11 and configured, shaped and dimensioned to form aninternal narrow electron beam 46 of a shape and configuration that cantravel through the nozzle 12 and emerge out the exit window 42 aselectron beam 44. The configuration of the electrostatic lens 30, thediameter of the opening 36 in electrostatic lens 30, the distance H atwhich the electrostatic lens 30 is positioned from the opening 38, thediameter D₅ of the opening 38. and the orientation and configuration offilament 32, can be arranged or configured so that the electrons e⁻exiting the electron generator 24 exit in a desired configuration. Theinternal electron beam 46 can exit the electron generator 24 in a mannerthat narrows or converges in a narrowing or converging portion 46 a. Thediameter D₄ of the housing 26 can be generally about the same diameteras the inner diameter D₃ of the nozzle 12, and the diameter D₅ of theopening 38 of the housing 26 can be smaller than the inner diameter D₃of the nozzle 12. This can allow the converging portion 46 a of theinternal electron beam 46 to enter the narrow nozzle 12 with little orno blockage. The distance of the electron generator 24 can be alsosufficiently spaced from the axial proximal end of the nozzle 12 toallow the converging portion 46 a to enter. The internal electron beam46 can converge at a convergence or focus point 46 b within the nozzle12, and then widen, diverge or spread out in a widening, spreading ordiverging portion 46 c before exiting the exit window 42 in a widening,spreading or diverging external electron beam 44. The electron beam 44can direct electrons e⁻ away from the exit window 42 longitudinallyalong the longitudinal axis “X” as well as circumferentially radiallyoutward relative to axis “X”. The electron beam 44 can have an outwardlyangled conelike shape. In some embodiments, the diameter D₄ of thehousing 26 and the diameter D₅ of the opening 38 can be larger than theinner diameter D₃ of the nozzle 12. In such a situation, the electrongenerator 24 can be configured and spaded a sufficient distance L₂ toprovide an internal electron beam 46 with a converging portion 46 a thatsufficiently narrows or converges to enter nozzle 12, and a divergingportion 46 b that reaches the exit window 42.

The narrowing or converging, and then widening or divergingconfiguration of the internal electron beam 46 can keep the internalelectron beam 46 narrow while within the nozzle 12 to allow travel ofthe beam 46 therethrough, and can allow the use of long narrow nozzles12. For example, in some embodiments, the length L₁ to inner width ordiameter D₃ ratio of the nozzle 12 can be at least about 3:1, forexample about 6:1 or greater, and in other embodiments, about 10:1 orgreater. In addition, the ratio of the width or diameter D₁ of thevacuum chamber 11 to the outer width or diameter D2 of the nozzle 12 canbe about 2:1, and in other embodiments about 3:1. Depending upon theapplication at hand, these ratios can vary. In some embodiments, thebeam 46 can be formed in only a diverging manner, but may result in ashorter nozzle for a given inner diameter D₃, and can be about half aslong. In some embodiments, the nozzle 12 can be tapered. Theconfiguration of the electron generator 24, and distances L₂ and L₃, canbe adjusted to provide the desired internal electron beam 46configuration to enter a nozzle 12 of a given length L₁ an innerdiameter D₃, and obtain a desired electron beam 44 configuration exitingthe exit window 42. The nozzle 12 can have different lengths L₁, andouter widths or diameters D₂, for insertion into different sizedcontainers or bottles 20. For example, different sized nozzles 12 can beemployed for 12 oz. bottles 20 and 32 oz. or 2 liter bottles 20. Forexample, wider nozzles 12 can be used for wider bottles 20 with widernecks 16, and longer nozzles 12 can be used for taller bottles 12. Insome embodiments, the same nozzle 12 can be used in a range of differentsized containers of bottles 20.

The vacuum chamber 11 and nozzle 12 can be formed of metal, ceramics, ora combination thereof. In one embodiment, the vacuum chamber 11 can havea width or diameter of about 2 inches. Vacuum chamber 11 can have largeror smaller widths and diameters depending upon the application at handand the desired power levels. The housing 26 of the electron generator24 can be formed of conductive material, for example metal, such asstainless steel. Filament 32 can be formed of a suitable material suchas tungsten. The electron beam emitter 10 can be operated in a rangebetween about 40 to 150 KV, and about 0 to 5 milliAmps. Alternatively,higher or lower voltages can also be used. It is understood thatdimensions and voltage and power levels can vary depending upon theapplication at hand. Some features of the electron beam emitter 10 canbe similar to embodiments disclosed in U.S. Pat. Nos. 5,962,995,6,407,492, and 6,545,398, the contents of which are incorporated hereinby reference in their entirety.

The exit window 42 can extend across substantially the width of theinner diameter D₃ of the nozzle 12 at the axial distal end 14. The exitwindow 42 can be formed of suitable materials, for example, titaniumhaving a thickness of 12.5 microns or less. In some embodiments, thethickness can be between about 4-12 microns thick. Other embodiments canhave larger or smaller thicknesses. The exit window 42 can have acorrosion resistant covering, for example, gold, diamond, etc. The exitwindow 42 can be sealed or bonded to the nozzle 12 to preserve ahermetically sealed vacuum with nozzle 12 and vacuum chamber 11. Asupport plate with holes therethrough can be used to support the exitwindow 42. Other suitable materials and configurations can be employedfor exit window 42. Exit window 42 can include constructions disclosedin U.S. application Ser. No. 10/751,676, filed Jan. 5, 2004, thecontents of which are incorporated herein by reference in its entirety.In some embodiments, a support plate can be omitted. In addition, theexit window 42 can be formed of corrosion resistant material without alayer of titanium.

In another embodiment, the exit window 42 can be a target window beingmade of a material and having a thickness sufficient to substantiallyprevent the passage of electrons e⁻ through from the internal electronbeam 46 while forming and allowing the forward passage of x-rays,thereby providing an x-ray beam emitter for emitting forward x-ray beamsthrough a narrow nozzle 12. The target window can include a thin foil ofgold, titanium, or tungsten, or titanium having a layer of gold, or goldwith copper or silver. Typically, metals with a high Z number and goodthermal conductivity are employed, but materials can vary depending uponthe situation at hand.

While this invention has been particularly shown and described withreferences to example embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims.

For example, although the vacuum chamber 11 and nozzle 12 have beendescribed to have generally circular peripheries, in other embodiments,the peripheries can be of other suitable shapes, for example, polygonal,such as triangular, rectangular, square, hexagonal, octagonal, etc., ornon-circular curves for example, oval, egg shaped, etc. In someembodiments, the electron beam emitter 10 can be used for irradiatingthe interior of containers and bottles for purposes other thansterilization, or neutralization for example, for curing, surfacetreatment, etc.

1. A method of irradiating an interior of a bottle for sterilizing theinterior of the bottle, the bottle having a neck, the method comprising:generating electrons with an electron generator positioned within avacuum chamber, the vacuum chamber having a width; extending anelongated nozzle from the vacuum chamber along a longitudal axis, thenozzle having an exit window at a distal end of the nozzle, the nozzlehaving a width that is less than the width of the vacuum chamber;forming and directing an electron beam that enters and travels throughthe nozzle, and exits out the exit window; inserting the nozzle throughthe neck of the, bottle and irradiating the interior with the electronbeam; and moving the bottle and the nozzle relative to each other duringirradiation to an extent that depends upon a size of the bottle.
 2. Themethod of claim 1 wherein moving the bottle and the nozzle relative toeach other during irradiation further depends upon a diameter of thebottle.
 3. The method of claim 1 wherein moving the bottle and thenozzle relative to each other during irradiation further depends upon anintensity of the electron beam.
 4. The method of claim 1 wherein theinterior of the bottle has an ambient gaseous environment, the methodfurther comprising modifying the gaseous environment within the bottle.5. The method of claim 1 further comprising assisting distribution ofthe electron beam within the interior of the bottle with at least oneelectron directing member adjacent to the bottle.
 6. The method of claim1 wherein the electron generator comprises a housing and the electronbeam exits the electron generator housing in a narrowing manner.
 7. Amethod of irradiating an interior of a bottle for sterilizing theinterior of the bottle, the bottle having a neck, the method comprising:generating electrons with an electron generator positioned within avacuum chamber, the vacuum chamber having a width; extending anelongated nozzle from the vacuum chamber along a longitudal axis, thenozzle having an exit window at a distal end of the nozzle, the nozzlehaving a width that is less than the width of the vacuum chamber;forming and directing an electron beam that enters and travels throughthe nozzle, and exits out the exit window; inserting the nozzle throughthe neck of the bottle and irradiating the interior with the electronbeam; and moving the bottle and the nozzle relative to each other duringirradiation to an extent that depends upon a diameter of the bottle. 8.The method of claim 7 wherein moving the bottle and the nozzle relativeto each other during irradiation further depends upon a size of thebottle.
 9. The method of claim 7 wherein moving the bottle and thenozzle relative to each other during irradiation further depends upon anintensity of the electron beam.
 10. The method of claim 7 wherein theinterior of the bottle has an ambient gaseous environment, the methodfurther comprising modifying the gaseous environment within the bottle.11. The method of claim 7 further comprising assisting distribution ofthe electron beam within the interior of the bottle with at least oneelectron directing member adjacent to the bottle.
 12. The method ofclaim 7 wherein the electron generator comprises a housing and theelectron beam exits the electron generator housing in a narrowingmanner.
 13. A method of irradiating an interior of a bottle forsterilizing, the bottle having a neck, the method comprising: generatingelectrons with an electron generator positioned within a vacuum chamber,the vacuum chamber having a width; extending an elongated nozzle fromthe vacuum chamber along a longitudal axis, the nozzle having an exitwindow at a distal end of the nozzle, the nozzle having a width that isless than the width of the vacuum chamber; forming an electron beam thatenters and travels through the nozzle, and exits out the exit window;inserting the nozzle through the neck of the bottle and irradiating theinterior with the electron beam; and moving the bottle and the nozzlerelative to each other during irradiation that depends upon an intensityof the electron beam.
 14. The method of claim 13 wherein moving thebottle and the nozzle relative to each other during irradiation furtherdepends upon a size of the bottle.
 15. The method of claim 13 whereinmoving the bottle and the nozzle relative to each other duringirradiation further depends upon a diameter of the bottle.
 16. Themethod of claim 13 wherein the interior of the bottle has an ambientgaseous environment, the method further comprising modifying the gaseousenvironment within the bottle.
 17. The method of claim 13 furthercomprising assisting distribution of the electron beam within theinterior of the bottle with at least one electron directing memberadjacent to the bottle.
 18. The method of claim 13 wherein the electrongenerator comprises a housing and the electron beam exits the electrongenerator housing in a narrowing manner.